Stimuli-responsive membranes for targeted delivery of actives

Identifier:  TDX:3117

Handle: https://hdl.handle.net/20.500.11797/TDX3117

Authors:  Del Pezzo, Rita

Abstract:
In this work the attention will be mainly drawn on the design, the preparation and the characterization of light sensitive microcapsules, which are able to release the payload under white light irradiation. Although the main reason for encapsulation is the necessity to store and protect an active ingredient into a physically and chemically stable shell, in commercial applications can be important also to control the release over time. This is the main reason why we want to develop an easy, cheap and robust chemistry to produce capsules responsive to external stimuli. Among other external stimuli light was selected to control the release of fragrances. For this purpose, the core-shell capsules morphology was found to be the most suitable, and the azobenzene, among other chromophores, was selected as photo-isomerizable unit and building block of the capsule’s polymeric shell. Azobenzene derivatives in fact, were designed and synthesised to be incorporated in the capsule’s shell as its main constituent. The design included the functionalization of un-modified azobenzene with proper side groups which allow the isomerization of the whole molecule to undergo with white light, and subsequent incorporation of the new light-sensitive unit into different systems as polymeric linear chains or crosslinked nets.